Usually Lego Technic models are based on square patterns of holes which in turn are based on the Lego length unit “1 stud”.

The problem is when you want to attach a leaning liftarm to your (square) construction, how do you find the correct holes to attach it to? Usually the leaning liftarm “almost” fits.

I translated the issue into a mathematical problem. The base is of course a right triangle with the condition that all sides must be an integer. The phenomenon is called Pythagorean triples. (google it). I found the following triples especially interesting for the context of Lego.

3-

4-

56-8-105-12-13

Then I realized that Lego also “supports” “half stud” constructions which also enable the following combinations:

1,5-2-2,52,5-6-6,5

Note that the numbers above corresponds to the length between the first and last hole in a liftarm. To translate the length into the number of holes of the liftarms you have to add one (1). Below you can see the examples of the variations.

2014/03/10

Designing a complex Lego Technic model requires a lot of planning, thinking and building. I left my "dark ages" during the summer of 2010. Since then I have recurrent periods where I build a few hours every week. However, within those I periods, I find myself completely stuck. In this article I will give you my best tricks for fluent building!

2014/01/11

There has been a debate on how to build proper articulated steering with the use of double linear actuators (LA). The problem is that the steering ”speed” will vary over the steering ”cycle” when only using a single LA. As a result, when using double LA:s, there will tensions, that might be large enough to engage the built in clutches in the LA:s. However, depending on how you choose your ”geometry”, this problem can be reduced. This video shows one example of a geometry that will work fairly well, using the mini LA:s. It has been tested in vehicle up to 70 cm / 2 kg.

2014/01/03

2013/08/10

I was not really happy with the first version of my telehandler, the design was nice but it performed quite badly, especially the weak propulsion and poor suspension. For some reason the tires almost tore off the axles when it drove a meter or so and it looked like the suspension was really weak, which it wasn’t.

With the Grand Prix Racer (42000) set a new suspension system was introduced. I decided to have another go at building a Telehandler. I tried to keep the design as far as possible but reworked the entire chassis and used a PF L-motor for propulsion and the PF Servo for steering.

I am really proud about how small but still robust I could make the chassis. In the picture you can see the entire chassis housing:

2x PF L-motor

1x PF M-motor

1x PF Servo motor

1x Battery Pack

3x PF IR Receivers

However, It performed almost worse than the first version and I can’t get why. The tires do everything they can to rip apart which in turn affects the steering and propulsion. I am almost in doubt whether it is possible to build a 4 wheel driven and steered chassis with pendular suspension..